Parabola

Signed-In Members Don't See This Ad
See more from Chasper

Chasper

Member
Joined
Mar 22, 2007
Messages
1,987
Location
Indiana
Its seriously fun to have kids who come home from school with algebra assignments to make things like this. On a clear day it will ignite a newspaper in 4 seconds and boil a cup of water dry in 4 minutes.
 

Attachments

  • Parabola.jpg
    Parabola.jpg
    54.3 KB · Views: 398
Signed-In Members Don't See This Ad

rwyoung

Member
Joined
Feb 21, 2009
Messages
145
Location
Lawrence, KS
Never made the parabola type but I did make one heck of an ant-burner using a frensel lens once. Rollie-pollies (sow bugs) are kinda like popcorn.
 

Chasper

Member
Joined
Mar 22, 2007
Messages
1,987
Location
Indiana
Will you share the plans?

Here you go: Ax² + By² + Cx + Dy + E = 0 (if you really need to know what that means I'll have to ask my kids) Once you determine the y you want to use you graft it life size.

We started by turning a very shallow but thick bowl (8" diameter X 4" thick with less than 1/2' bowl indention) and cutting 16 notches in it around the edges; it looks like a big gear. Then we used the life sized graph cut out to cut 16 ribs out of thin plywood; the ribs are about 30 inches long and they curve up 12 inches, each rib plus the radius of the hub combine to the radius of the parabols, about 33" in this case. The bowl is covered with thin sheet aluminum and it is covered with mylar.

The algebra is in the quadratic equation to get the curve right so the heat reflection all goes to one spot in the center directly at the bottom of the cooking vessel. http://www.mathwarehouse.com/quadratic/parabola/interactive-parabola.php go here for more info.
 
Last edited:

jleiwig

Member
Joined
Jan 10, 2007
Messages
1,860
Location
Monroe, Ohio, USA.
look up tracking solar concentrator on google. There are plans out there. Makes one hell of a water heater! It was a green solution developed back when being green wasn't cool like it is today.
 

btboone

Member
Joined
Dec 5, 2004
Messages
2,421
Location
Roswell, GA, USA.
I had made one about 6 feet across when I was in school. I cut a couple thousand mirror sections and glued them to a steel sheetmetal frame. It worked well and would melt lead.
 
Top Bottom